Multimodality Imaging in Cardiac Amyloidosis: Part 2 of 2—Diagnostic Criteria and Appropriate Utilization
Recommendations
Expert Consensus Recommendations for Diagnosis of Cardiac Amyloidosis
| Criteria for Diagnosis | Subtype |
| Histological Diagnosis of Cardiac Amyloidosis: Endomyocardial Biopsy* | |
| lL. Endomyocardial biopsy positive for cardiac amyloidods with Congo red staining with apple-green birefringence under polarized light; typing by immunohistochemistry and/or mass spectrometry at specialized centers | AL, ATTR, Other subtypes |
| Histological Diagnosis of Cardiac Amyloidosis: Extracardiac Biopsy | |
| l. ATTR cardiac amyloidosis is diagnosed when below criteria are met: a. Extracardiac biopsy proven ATTR amyloidosis AND b. Typical cardiac imaging features (as defined below) |
ATTR |
| 2. AL cardiac amyloidosis is diagnosed when below criteria are met: a. Extracardiac biopsy-proven AL amyloidosis AND b. Typical cardiac imaging features (as defined below) OR c. Abnormal cardiac biomarkers: abnormal age-adjusted NT-pro BNP or abnormal troponin T/I/Hs-Troponin with all other causes for these changes excluded |
AL |
| Clinical Diagnosis of ATTR Cardiac Amyloidosis: 99mTc-PYP, DPD, HMDP | |
| 3. ATTR cardiac amyloidosis is diagnosed when below criteria are met: a. 99mTc-PYP, DPD, HMDP Grade 2 or 3 myocardial uptake of radiotracer AND b. Absence of a clonal plasma cell process as assessed by serum FLCs and serum and urine immunofixation AND c. Typical cardiac imaging features (as defined below) |
ATTR |
| Typical Imaging Features of Cardiac Amyloidosis | |
| Typical cardiac echo of CMR or PET features: ANY of the below imaging features with all other causes for these cardiac manifestations, including hypertension, reasonably excluded. | |
| 1. Echo a. LV wall thickness >12 mm b. Relative apical sparing of global LS ratio (average of apical LS/average of combined mid+basal LS >1) c. ≥Grade2 diastolic dysfunction† |
ATTR/AL |
| 2. CMR a. LV wall thickness >ULN for sex on SSFP cine CMR b. Global ECV >0.40 c. Diffuse LGE† d. Abnormal gadolinium kinetics typical for amyloidosis, myocardial nulling prior to blood pool nulling |
ATTR/AL |
| 3. PET: 18F-florbetapir or 18F-florbetaben PET† ‡ a. Target to background (LV myocardium to blood pool) ratio >1.5 b. Retention index >0.030 min-1 |
ATTR/AL |
LGE, late gadolinium enhancement; LS, longitudinal strain; SSFP, steady-state free precession; ULN, upper limit of normal, per Kawel et al39 at mid-cavity level ULN for women/men were 7/9mm (long axis) and 7/8mm (short axis), respectively.
These consensus recommendations were based on moderate-quality evidence from one or more well-designed, well-executed nonrandomized studies, observational studies, registries, or meta-analyses of such studies. The PET recommendations were based on more limited data.
* Endomyocardial biopsy should be considered in cases of equivocal 99mTc-PYP, DPD, HMDP scan. When 99mTc-PYP, DPD, HMDP is positive in the context of any abnormal evaluation for serum/urine immunofixation or serum free light-chain assay, or MGUS, this should not be seen as diagnostic for ATTR cardiac amyloidosis. In these instances, referral to a specialist amyloid center for further evaluation and consideration of biopsy is recommended.
† Off-label use of FDA-approved commercial products.
‡ 18F-flutemetamol not studied systematically in the heart. 11C-Pittsurgh B compound is not FDA approved and not available to sites without a cyclotron in proximity.
Overview
Title
Multimodality Imaging in Cardiac Amyloidosis: Part 2 of 2—Diagnostic Criteria and Appropriate Utilization
Authoring Organization
Society of Nuclear Medicine and Molecular Imaging